#46 NullPointerException in InstancePeer.getPeer()

[Dimitry D\'hondt]

Our application has been running on Echo in a
production environment for some months now. About 1 to
5 times per week we get 1 exception on a web request
where the InstancePeer is not able to look up the
component peer.

Most likely this is a very rare bug because it appears
on random components and very infrequent as stated above.
Our application has about 100.000 web requests per day.
So the error seems to appear every 1 in +- 500.000 web
requests. (Rough numbers)

The exception thrown is this :

java.lang.NullPointerException
at
nextapp.echoservlet.InstancePeer.getPeer(InstancePeer.java:621)
at
nextapp.echoservlet.ComponentPeer.getPeer(ComponentPeer.java:271)
at
echopoint.ui.util.EchoPointComponentPeer.getPeer(EchoPointComponentPeer.java:102)
at
echopoint.ui.DialogPanelUI.render(DialogPanelUI.java:265)
at
nextapp.echoservlet.ui.GridCellUI.render(GridCellUI.java:114)
at nextapp.echoservlet.ui.GridUI.render(GridUI.java:273)
at
nextapp.echoservlet.ui.GridCellUI.render(GridCellUI.java:114)
at nextapp.echoservlet.ui.GridUI.render(GridUI.java:273)
at
nextapp.echoservlet.ContentPaneUI.service(ContentPaneUI.java:275)
at
nextapp.echoservlet.Connection.process(Connection.java:459)
at
nextapp.echoservlet.Hack.processConnection(Hack.java:27)
at com.dhl.hydrogen.echo.Server.process(Server.java:149)
at
nextapp.echoservlet.EchoServer.doGet(EchoServer.java:224)
at
javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at
javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at
com.dhl.hydrogen.servletfilter.GZipFilter.doFilter(GZipFilter.java:45)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at
com.dhl.hydrogen.servletfilter.ContextFilter.doFilter(ContextFilter.java:79)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at
org.securityfilter.filter.SecurityFilter.doFilter(SecurityFilter.java:182)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2422)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:163)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:577)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at
org.apache.ajp.tomcat4.Ajp13Processor.process(Ajp13Processor.java:457)
at
org.apache.ajp.tomcat4.Ajp13Processor.run(Ajp13Processor.java:576)
at java.lang.Thread.run(Thread.java:534)